The Complete Guide to Aluminum Metal

When you look at modern engineering marvels, from commercial airliners cruising at 35,000 feet to high performance automotive frames, you are looking at the power of aluminum. Standard carbon steel is incredibly strong, but its massive weight is a severe liability in industries where speed and efficiency matter. When engineers need to shed weight without sacrificing structural integrity, they turn to the world’s most popular non-ferrous metal.

If you are an aerospace manufacturer, a marine contractor, or a precision fabricator, selecting the correct grade of aluminum is just as critical as selecting the right steel. Using the wrong alloy can lead to premature metal fatigue, poor weld quality, and structural failure.

At Warrenton Steel, we treat our partners’ projects with the utmost precision. As a proudly veteran owned metal supplier operating since 1989, we understand that true industrial expertise extends far beyond iron and carbon. Our ISO 9001:2015 and AS 9100D certifications demand rigorous quality control over our entire inventory, ensuring we provide St. Louis and the Midwest with exactly what the job requires.

This guide will break down the exact definition of aluminum, explore its unique mechanical advantages over steel, and detail the most common industrial alloys available for your next major build.

What is Aluminum Metal?

Aluminum is a lightweight, highly conductive, non-ferrous metal. Because it contains no iron, it naturally resists corrosion by forming a protective oxide layer when exposed to air. It offers an exceptional strength to weight ratio, making it the foundation of modern aerospace, automotive, and marine manufacturing.

This definition highlights the core reason aluminum is so valuable. It is approximately one third the density of steel. While a raw piece of aluminum cannot support the massive compressive load of a steel I beam, its low weight allows engineers to build incredibly strong structures that are light enough to fly, float, and accelerate efficiently.

The Core Properties of Aluminum

When you source aluminum for a commercial project, you are actively choosing to prioritize specific physical behaviors over pure bulk strength. Here is what makes this material an industrial powerhouse.

Exceptional Strength to Weight Ratio

This is the primary driver of aluminum consumption. By alloying aluminum with elements like copper, magnesium, or zinc, metallurgists can create a metal that approaches the yield strength of certain steels while remaining incredibly light. This ratio is what makes modern air travel possible.

Natural Corrosion Resistance

Unlike carbon steel, which aggressively rusts when exposed to moisture, aluminum protects itself. When raw aluminum touches oxygen, it instantly forms a microscopic layer of aluminum oxide on its surface. This layer seals the metal, preventing further decay. If the metal is scratched, the layer heals itself immediately. This makes aluminum highly desirable for outdoor architectural features, boat hulls, and harsh weather environments.

High Electrical and Thermal Conductivity

While copper is the gold standard for conductivity, aluminum is an incredibly close second. More importantly, it is significantly lighter and cheaper than copper. For this reason, high voltage power transmission lines spanning across the country are almost entirely made of aluminum cables reinforced with a steel core. It is also heavily used in manufacturing heat exchangers and automotive radiators.

High Malleability and Machinability

Aluminum is generally much softer than steel. This makes it incredibly easy to extrude into complex, intricate shapes (like window frames or heat sinks) without fracturing the metal. It also allows for rapid, high speed machining, saving commercial fabrication shops significant time and tool wear.

The Heavy Hitters: 6061 vs 7075 Aluminum

In industrial and aerospace manufacturing, “pure” aluminum is rarely used because it is too soft. Instead, it is alloyed with other elements. The Aluminum Association uses a four digit naming system to classify these alloys.

When our partners place an order, the conversation almost always centers around two specific structural grades: 6061 and 7075.

6061 Aluminum (The Industry Standard)

The 6000 series is alloyed with magnesium and silicon. 6061 is the absolute workhorse of the aluminum world.

• Properties: It strikes the perfect balance. It is highly formable, incredibly easy to machine, and possesses excellent corrosion resistance. Crucially, it is very easy to weld using standard TIG or MIG processes.

• Common Uses: Structural framing, marine hardware, automotive parts, bicycle frames, and general commercial fabrication.

7075 Aluminum (The Aerospace Standard)

The 7000 series is alloyed primarily with zinc. This drastically changes the internal structure of the metal, transforming it into an absolute powerhouse.

• • Properties: 7075 is one of the strongest aluminum alloys in existence, boasting a yield strength that matches or exceeds many types of carbon steel. However, this massive strength comes at a cost. It is much harder, less formable, and significantly more expensive. More importantly, it is generally considered non weldable, meaning parts must be joined with mechanical fasteners (like rivets).

  • Common Uses: Military aircraft frames, aerospace components, high performance firearms, and heavy duty rock climbing equipment.